Galaxy Study - Deep Sky Videos

right now I'm doing one of the less fun tasks of being an astronomer Brady may get the exotic trips to wonderful telescopes but sometimes when we get a wordid time on telescopes we don't actually physically get to go but we still have to set up all of the observations and make all the instructions clear enough that those people working at the telescope are able to do what we wanted them to do so what I have here is an application that I wrote back in September for time on the very large telescope in Chile at the European Southern Observatory it's called the dynamical state of the double cluster Abell 2465 twice a year calls for proposals come out you put a proposal in say this is what I want to do this is how much time I need to do it in it gets reviewed by a panel there are there are many many many applications that go in for this because telescope time is very competitive it's a very valuable resource and just before Christmas I got the announcement that my telescope time a proposal had been successful it's just because you get telescope time awarded doesn't mean that you actually get the data there's a long road ahead now traditionally in old fashioned schemes you'd actually be allocated a particular night and say right July 25th to 31st that's your night to go to the telescope do what you want make your observations that still does happen in some facilities but the larger our facilities get the more complicated they get the more we realize that it's not a very efficient way to run an observatory so now many observatories are moving towards queue scheduling which means that you don't get allocated a night you simply get allocated a priority you put your instructions into the queue if the conditions are correct and your object is visible your instructions may get executed they might not be all executed on the same night unless that's required they might not all get done at all you lose the fun of going out to these wonderful exotic observatories but also you don't end up with the frustration of sitting on a mountaintop for seven nights waiting for the clouds to clear which I have done so the queue system there are pros and cons to it it means that it's more likely that if your project is awarded time it actually gets executed but it does mean less fun and less travel involved for us I had my fingers crossed for this I'm very pleased that it got time however it wasn't ranked top of the list which means it's a little bit further down in the priority ranking which means there's a good chance that these observations won't actually get done at all because higher priority programs will have first call on the time under what circumstances will you get in what are you hoping will happen well we have a bit of luck up our sleeves in this in the sense that for these particular observations we don't need the very very best observing conditions we need to be able to see our objects but the atmospheric conditions don't have to be quite as strict and and perfect as some other programs might need that means that if on a night what we call the seeing the the the ability to to resolve objects in the sky if the scene gets a little worse the app atmosphere gets a little turbulence other programs might not get executed and ours might pop up to the top of the queue so in a sense we're we're actually hoping for slightly poorer conditions because that's probably the only way that this particular program will get observed you're a very collaborative person and these are the ones have been ranked above you obviously for a reason surely it's more important to you even that they get done are you wishing bad luck on your colleagues of course not of course not it's it's it's a it's a question of efficiency there is there there's an inevitably going to be less perfect observing conditions so we want to make sure we have something in the queue to use that time up so the telescope's aren't sitting idle so the proposal is to look at not a galaxy cluster but a pair of galaxy clusters so this are two of the most massive objects in the universe that we can see on the sky sitting next to each other and one of my collaborators has been studying this object for a very very long time so the question we want to answer about this structure is that we have these two lumps of galaxies sitting next to each other we want to know if they're just about to merge or if in their history they've already merged and passed out through the other side you can see a collection of bright galaxies here and a collection of bright galaxies there what stars to me well there are some stars in the image but the this the fuzzier blobs are most likely galaxies from a picture we can't tell the direction of motion of these objects but we have another tool in our Arsenal as astronomers we can take images of an object or we can take spectroscopy of an object and by taking spectroscopy splitting the light up and looking at the different wavelengths of light being emitted from an object we can tell to first-order how far away it is or how fast it's moving it's one of these wonderful benefits that we get from living in an expanding universe however when you get to a complicated system like this it gets a little harder and that relationship is no longer quite so straightforward between the the redshift the stretching out of the light that we measure with our spectrograph and the distance we have to still gather this data but then we have to use much more complicated statistical analysis techniques to disentangle the actual relative motions so at the moment what I want to do with the VLT is get more spectra of these galaxies my collaborators have already gathered some for the brighter objects but now we're using the power of the VLT The Very Large Telescope to go after some of the fainter objects so at the moment I'm doing phase 2 preparation phase 1 was writing the proposal and getting the tongue now that we've been awarded the time Phase two is setting up the details of exactly what the instrument is going to do and how the object will be observed at the telescope I need to package up my instructions in units of one hour these are called observing blocks and that hour has to contain everything to do with setting up the instrument reading out the instruments doing the calibrations as well as actually taking the data and so those observing blocks will go into the queue and be executed one at a time by a machine or by humans so there will be the we program that manages the queue and there will be professional astronomers working at the telescope whose job it is to take to choose what comes out of the queue and execute those commands well I'm in the midst of it now so it's not finished and the deadline is fast approaching so I'm getting a little bit anxious about this but I'm using the software provided to us by the observatory that's written for this particular instrument so you see the image of the field of view that I'm looking at I have a catalog of galaxies that I may want to target and I've plotted some of likely targets up here in red and I have to explain that for doing spectroscopy it's different from imaging in the sense that we have to restrict the amount of light that comes into the camera we have to say only look at that particular galaxy the way we do this is by inserting a mask into the instrument that blocks out most of the light and part of the instructions that I'm creating here is a set of a pattern saying at the telescope using a laser cutting machine cut a hole at the position of each of the galaxies that I want to observe and so that's what I'm designing here I'm designing those masks so within this blue square I can tell the software to place a slit on some of these galaxies not all of them because they won't all fit but that's part of what I'm doing now I'm picking and choosing which galaxies will actually be observed so they're literally going to put a mask over the telescope like Zorro wears am I and cut holes in it so not over the telescope itself but within the instrument so the light will come into the telescope it'll bounce off the primary mirror off the secondary mirror into an instrument and in the midst of that optical path a mask will be placed that then splits up the light that comes specifically from the galaxies that I'm interested in so my job right now is to decide which galaxy is going to have slits put on them and I can do that simply by clicking on the galaxies and I I can then say write only light from this particular galaxy here is going to enter that slit and be spread out along the CCD detector so this is an extreme example of a mask with slits cut into it this is from some observing I did a few years ago also in Chile at a different telescope at Las Campanas Observatory when I actually got the opportunity to go and be there in person and this particular instrument is is designed so you put you cut many thousands of very very tiny slits and over a very very wide area so you observe many thousands of galaxies in a single night this is not the kind of instrument that I'm using for these observations that I'm describing today probably I'll only get about 40 galaxies in each one of my masks today simply because it's a different kind of instrument well I only have a day and a half to do it before the deadline so it's going to have to take me less than a day and a half these things always take a little bit longer there's always technical hitches and you have to learn the software and learn about the instrument but there is a bit of time pressure here so ya need to get working at all but it could all be for nothing it could all be for nothing yes

Channel: DeepSkyVideos

Views: 42,066

Rating: 4.9622641 out of 5

Keywords: VLT, very large telescope, chile, spectroscopy, telescope astronomy, astronomers, messier, space, galaxies, nebula, nebulae, stars, universe, deepsky, deepskyvideos, deep sky, telescope, Messier, Messier Objects, Messier Catalog, Messier Catalogue

Id: 8dzDvXqVcVA

Length: 10min 39sec (639 seconds)

Published: Thu Mar 01 2012